After working for the likes of Atari, Sony, and SEGA, Stolar became an advisor to Adscape Media in 2005. In 2007, he helped convince Google to purchase the company, which it renamed AdSense for Games.

'If you look at research, there are more people playing games than watching television. So what does that tell you? That tells you there's a whole different audience," Stolar said.

"The demographics have changed. So the rules have changed."

Even as more people of different age groups are playing games, companies need to take advantage of the new demographic without alienating players.

"At the end of the day, we can't piss off the customer. We can't over-populate a game with ads. If you're going to do that, you better give the game away for free," he said.

Sports games are the most obvious genre that integrates well with in-game ads, but Stolar thinks that fighting games and adventure games could also work well. Eventually, however, almost all genres will be subject to advertising.

"I would say 80 per cent of games [will have] advertising in them by 2010," Stolar predicted.